Frame rust, Line-X and undercoating

[RenoHuskerDu]

The F550 I just bought came from Iowa corn country and has rust damage up where it was difficult to rinse off. The rust is not structural but it looks like crap and I want this truck to be a keeper.

I found a local guy who will sandblast it for $200, which seems really fair. I just need to remove what I can and loosen up the wiring harness so's he can pull it aside.

I had the idea to get the frame Line-X'd after it was clean, so I called a guy I trust who does a lot. His entire 70s Blazer's sheet metal is Line-X'd, for example. He said heck, he'd take my money, but I should not do it. Too many problems with getting a good ground on the frame for lights etc, and there's always some pocket or three of rust under the coating. His suggestion after sandblasting is to just buy some cans of that nasty sticky 3M undercoating and have at it like a rattle can paint job.

Anybody BTDT?

[Danny G]

Neither is a good Idea, the rattle cans are not that great and linx will probably allow rust to form under it, as you mentioned.

I would hit the whole thing with a proven rust preventative/converter like Eastwoods Chassis saver, a POR product, or Corroseal, then paint over top of that. Any place you need a ground at you can sand/grind clean install your ground and seal the whole area up with some polysulfide sealant.

[Gary Lewis]

Neither is a good Idea, the rattle cans are not that great and linx will probably allow rust to form under it, as you mentioned.

I would hit the whole thing with a proven rust preventative/converter like Eastwoods Chassis saver, a POR product, or Corroseal, then paint over top of that. Any place you need a ground at you can sand/grind clean install your ground and seal the whole area up with some polysulfide sealant.

I agree. A rust converter will bond VERY tightly to the rust, but not quite as well to bare metal. So some people prefer to use the rust converter on rusty metal, although you have to have the loose stuff off in order to do that. Others have said they leave their clean metal out in the elements to surface rust and then paint it on that.

But the way POR recommends is to use a phosphate etching material and then hit it with their rust converter. The phosphate etches the metal to provide a texture into which the paint can settle an to which it can grip. I've done that, but I've also used POR-15 on freshly media-blasted parts and it has adhered extremely well.

Also, many rust converters are not UV stable and they turn white over time if they get hit with UV. So it is recommended that you top-coat them to protect them. POR sells a top coat for use on their rust converter. I've had good luck with it, but find it VERY difficult to tell where I've painted the top coat on if the POR-15 is black. So I do one of two things now:

• Use the POR silver rust converter so I can tell where I've painted the Chassis Black top coat

• Spray a good quality Chassis Black top coat with a rattle can

Either of those has to be done will the rust converter is tacky, and spraying is MUCH faster, so that's my preferred way now. I can't say that it is as durable as the POR top coat since I've not been doing it that long, but it sure seems to work.

 

[Rembrant]

Anybody BTDT?

The frame in my '84 was not pretty. I was going to have it sand blasted, but I decided on a different approach. I cleaned mine with wire cup wheels on angle grinders, and then just regular wire wheels in a hand drill in some spots. I got it as clean as possible.

I cleaned the grease and dirt and crap off of it with brake cleaner and lacquer thinner in the tougher spots.

I then applied Ospho Rust Treatment by hand (with a brush) and really soaked it down. You can see below how it all turned white on the residual rust that was remaining...and was dripping on the floor. http://www.ospho.com/

I let that dry for 24 hours, and then primed with a rust primer.

And then sprayed gloss black rust paint, and so far it has been standing up pretty well.

Would I have liked to strip the frame bare and have it sand blasted? Absolutely. However, time and space, etc was a problem for me. I did the best I could with what I had to work with.

PS: Just to add, I painted with a paint gun, and had to really thin out the rust paint to get it to spray at all. The good news was that it went on good and thick...I didn't really have much choice. However, it seems to be a nice hard coating yet it is flexible enough to have no problems on the frame.

 

[ArdWrknTrk]

Anybody BTDT?

The frame in my '84 was not pretty. I was going to have it sand blasted, but I decided on a different approach. I cleaned mine with wire cup wheels on angle grinders, and then just regular wire wheels in a hand drill in some spots. I got it as clean as possible.

I cleaned the grease and dirt and crap off of it with brake cleaner and lacquer thinner in the tougher spots.

I then applied Ospho Rust Treatment by hand (with a brush) and really soaked it down. You can see below how it all turned white on the residual rust that was remaining...and was dripping on the floor. http://www.ospho.com/

I let that dry for 24 hours, and then primed with a rust primer.

And then sprayed gloss black rust paint, and so far it has been standing up pretty well.

Would I have liked to strip the frame bare and have it sand blasted? Absolutely. However, time and space, etc was a problem for me. I did the best I could with what I had to work with.

PS: Just to add, I painted with a paint gun, and had to really thin out the rust paint to get it to spray at all. The good news was that it went on good and thick...I didn't really have much choice. However, it seems to be a nice hard coating yet it is flexible enough to have no problems on the frame.

I'm in the phosphoric acid and paint camp.

Kleenstrip metal and concrete prep was $18 a gallon @ Home Depot.

It dilutes about 4-5:1.

Converting ferrous and ferric oxide to phosphates.

It will soak into crevices that you could never abrasively clean, and gets right down to solid steel.

Harbor Freight has an HVLP paint gun for $9.97 right now.

But a couple and toss them if they get bad, or use them as donors for the next one.

I thin Rustoleum with *turpentine* and spray that on too.

Get a bigger fluid tip if you can't spray enough solids to cover.

[Danny G]

I'm in the phosphoric acid and paint camp.

Kleenstrip metal and concrete prep was $18 a gallon @ Home Depot.

It dilutes about 4-5:1.

Converting ferrous and ferric oxide to phosphates.

It will soak into crevices that you could never abrasively clean, and gets right down to solid steel.

Harbor Freight has an HVLP paint gun for $9.97 right now.

But a couple and toss them if they get bad, or use them as donors for the next one.

I thin Rustoleum with *turpentine* and spray that on too.

Get a bigger fluid tip if you can't spray enough solids to cover.

This is a great option, straight chemistry Fe2O3 +H3PO4 -> FePO4. I didn't realize kleenstrip was phosphoric acid. This is the same process used to make the Iron Pillar of Delhi rust proof. That pillar is over 1600 years old and has no top coat. SO doing that to your frame is sure to make it utterly rust proof.

Talking about top coat. It would seem the frame needs some pretty durable paint. So is ceramic paints like POR-15 and other engine paints the way to go?

[ArdWrknTrk]

I'm in the phosphoric acid and paint camp.

Kleenstrip metal and concrete prep was $18 a gallon @ Home Depot.

It dilutes about 4-5:1.

Converting ferrous and ferric oxide to phosphates.

It will soak into crevices that you could never abrasively clean, and gets right down to solid steel.

Harbor Freight has an HVLP paint gun for $9.97 right now.

But a couple and toss them if they get bad, or use them as donors for the next one.

I thin Rustoleum with *turpentine* and spray that on too.

Get a bigger fluid tip if you can't spray enough solids to cover.

This is a great option, straight chemistry Fe2O3 +H3PO4 -> FePO4. I didn't realize kleenstrip was phosphoric acid. This is the same process used to make the Iron Pillar of Delhi rust proof. That pillar is over 1600 years old and has no top coat. SO doing that to your frame is sure to make it utterly rust proof.

Talking about top coat. It would seem the frame needs some pretty durable paint. So is ceramic paints like POR-15 and other engine paints the way to go?

I pretty much use DTM industrial maintenance Alkyds.

Ben Moore Super Spec, Rust-Oleum commercial, whatever I can get that is used for exterior steel like stairs and guardrails.

There is something about turpines that causes tremendous capillary action and self leveling of these paints.

Sometimes I use a metallic salt dryer/hardner as well.

Insul-X makes one.

Cobalt used to be common, but like all things good, there was a downside to those constantly exposed to too much.

[Angelo Voltura]

I pretty much use DTM industrial maintenance Alkyds.

Ben Moore Super Spec, Rust-Oleum commercial, whatever I can get that is used for exterior steel like stairs and guardrails.

There is something about turpines that causes tremendous capillary action and self leveling of these paints.

Sometimes I use a metallic salt dryer/hardner as well.

Insul-X makes one.

Cobalt used to be common, but like all things good, there was a downside to those constantly exposed to too much.

When dad and myself did his truck we needle scaled it and then hit it with the wire wheel. Then we laid down some Loctite rust converter, primed it, top coated it with black paint and then hit it with rubberized undercoating in certain areas. Then we top coated it again. It hasn't rusted in 2 years or so since we did it. Later on we added dual tanks etc.

 

[RenoHuskerDu]

When dad and myself did his truck we needle scaled it and then hit it with the wire wheel. Then we laid down some Loctite rust converter, primed it, top coated it with black paint and then hit it with rubberized undercoating in certain areas. Then we top coated it again. It hasn't rusted in 2 years or so since we did it. Later on we added dual tanks etc.

I was actually able to blast off most of the scale from the frame where the rust was worst, up high under the bed in the back where it was nearly impossible to rinse off the magnesium chloride from Iowa winters.. The pressure washer just peeled it off. I also removed my outer wheels and took a look at what's on the insides of the dualies. There's rust there also. I'm looking at Corroseal now as the best choice for me. I'm wondering whether or not it's suitable to use on wheels where there could be some flex that might cause it to chip or crack.

Who has used Corroseal and is satisfied with it, or unhappy ?

[ArdWrknTrk]

I was actually able to blast off most of the scale from the frame where the rust was worst, up high under the bed in the back where it was nearly impossible to rinse off the magnesium chloride from Iowa winters.. The pressure washer just peeled it off. I also removed my outer wheels and took a look at what's on the insides of the dualies. There's rust there also. I'm looking at Corroseal now as the best choice for me. I'm wondering whether or not it's suitable to use on wheels where there could be some flex that might cause it to chip or crack.

Who has used Corroseal and is satisfied with it, or unhappy ?

I've used very similar 'rust converters' on static structures.

But again, I want to get RID of oxides, not turn them to a different oxide (Fe3O4) and I don't want anything resilient and water based (Latex) that has surface tension -that rust can get, and travel under.

,

Wrought iron patio furniture is not a truck frame, so I can't speak to magchloride exposure.

These products do have their place.